Ill 



ANATOMICAL AND PHYSIOLOGICAL STUDIES ON 



In the growth of both zones we see about the same relation. 

 These increase rapidly from birth till nine (or twelve) days and 

 after thai very slowly. These relations are shown clearly in 

 the ratios at 1 to 546, 12 to 546, and 20 to 546 days. While after 

 twelve days the ratios in total breadth and in each zone are 

 the same, 1:1.1, that for 1 to 546 days is smaller for the outer 

 zone than it is for the inner zone, thus the inner zone increases 



TABLE 9 



Radial breadth of the membrana basilaris measured between the foramina nervina 

 and ligamentum spirale in tadial sections — on age (chart 7, fig. 2) 



1 A rat 

 Right side 



of nine days 

 11 



which could 

 94 

 111 

 93 



hear, gave the 



103 

 104 

 104 



following 

 197 

 195 

 196 



1 : 1.1 



considerably after birth, while the outer zone does not grow, 

 as some authors have imagined, as much as the inner zone. 

 I will discuss this point later. 



Comparing the growths of the radial breadth of the inner 

 and outer zones, we find that the inner zone is relatively narrow 

 al nine -lay- thus the ratios between them are 1:1.4; after that 

 Period the inner zone increases rapidly, and even at twelve 

 ^e ratio becomes 1:1.1, which is almost the same as in 

 tin- adult, 1:1.2. 





